Supertet

The supertet is equal to {4,4,4,4}, {4,4(1)2} or {4,2/2} in BEAF.[1]. It can also be written 4{{{{4}}}}4, or 4 & 4, using the array of operator. The term was coined by Jonathan Bowers. It is decently close to a well-known combinatorial constant, Harvey Friedman's n(4).

Supertet can be computed in 3-bracket operator notation using the following process: